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Accurate palyno-analysis by S. Loboziak (from 1980 to 1983) of 28 samples from the Upper Givetian to the Middle Frasnian Blacourt, Beaulieu and Ferques Formations and of 44 samples of the Upper Frasnian to the Lower Famennian Hydrequent Formation are re-evaluated. Chelinospora concinna, Verrucosisporites bulliferus, Cirratriradites jekhowskyi, Lophozonotriletes media first occurrences are major criteria for Lower and Middle Frasnian, well calibrated by conodonts. Cymbosporites acanthaceus, Rugospora bricei, Grandispora gracilis, Diducites plicabilis, Corbulispora vimineus first occurrences allow to subdivide the Upper Frasnian where conodonts are poorly present. Samarisporites triangulatus versus Auroraspora pseudocrista taxonomy and stratigraphic significance are discussed. The reconnaissance borehole Nieuwkerke-De Seule (95W152), near the limit of the Upper Palaeozoic subcrop on the Brabant Massif (West Flanders, Belgium, 75 km east of the Boulonnais), which has intersected conodont-dated Givetian/Frasnian boundary at the transition between the Bois de Bordeaux and Bovesse Formations, contained poorly preserved miospores attributed to the triangulatus–concinna (TCo) Oppel Zones. In the nearby Nieuwkerke-Noordhoek borehole (95W153), strata also assigned to the Bovesse Formation yielded better preserved miospores which demonstrate a close succession of triangulatus–concinna (TCo) and bulliferus–jekhowskyi (BJ) Oppel Zones at the transition Lower–Middle Frasnian, also known in the Beaulieu Formation in the Boulonnais. Samples from the Heuvelland groundwater monitoring well (95W175), 10 km north of Nieuwkerke, contain the bricei-acanthaceus (BA) Oppel Zone suggesting a late Frasnian age, also known in the Hydrequent Formation in the Boulonnais area and in the Booischot Formation in the Booischot borehole (59E146) from the Campine Basin (Belgium). International correlation using Frasnian miospore zonation is attempted between the Pripyat Depression in Belarus, the Timan–Pechora province in Russia and North-West China.

The Alto Garcas Sub-basin in the northern part of the Parana Basin evolved differently from the Apucarana Sub-basin in the south. The marine environment was shallower in the Alto Garcas Sub-basin, which contains proportionately more silty and arenaceous rocks. The formations and members defined in the Apucarana Sub-basin are therefore difficult to apply in the Alto Garcas Sub-basin, where the Chapada Group (units 1–4) is more applicable. An integrated miospore and chitinozoan biozonation of the Chapada Group facilitates direct correlation between the Chapada Group’s units and the classical formations of the Parana Basin as defined in the Apucarana Sub-basin. The Furnas Formation and Chapada unit 1 constitute the same lithostratigraphic unit. Beds with rhyniophytes in the uppermost part of the Furnas Formation contain palynomorphs representative of the Si phylozone within the MN spore Zone (late Lochkovian), and the rhyniophyte beds occupy the same stratigraphic interval within Chapada unit 1 (the Lochkovian of the Parana Basin lacks chitinozoans). The lower part of Chapada unit 2 contains spores of the PoW Su spore Zone and chitinozoans of the Ramochitina magnifica and Ancyrochitina pachycerata zones, together indicating a late Pragian–early Emsian age-span. The upper part of Chapada unit 2 corresponds to the GS (AP) and Per (AD pre-Lem) spore Zones, and chitinozoans of the Ancyrochitina parisi, the informal Ancyrochitina varispinosa and Alpenachitina eisenacki chitinozoan zones, thus suggestive of a late Emsian – earliest Givetian age-span. Unit 3 is a proximal and lateral facies equivalent of the upper part of unit 2. The lower part of unit 4 includes spores typical of the early Givetian Lli (AD Lem) spore Zone and chitinozoans of the Ramochitina stiphrospinata chitinozoan Zone; the uppermost (early late Frasnian) part contains spores of the lower BMu (IV) spore Zone and chitinozoans of the Lagenochitina avelinoi chitinozoan Zone. The sandstones of unit 3 were inundated during the earliest Givetian, and the resultant flooding surface marks the base of unit 4 basin-wide. Clearly, the two sub-basins were distinct depositional centers during the Devonian.

A miospore biozonation, including 17 new interval zones, is proposed for Devonian–Early Carboniferous stratigraphic sections in the Amazon Basin. It results from a detailed review of the coeval miospore assemblages and biohorizons in the basin. The combined use of selected Euramerican and Western Gondwanan forms as zonal and characteristic taxa permits accurate subdivision, dating and correlation of Amazon Basin palyniferous strata in terms of equivalent miospore zones of Western Europe and the Old Red Sandstone Continent. The miospore data provide new insights into such varied issues as e.g. the age and stratigraphic relationships of regional rock units, the detection and dating of intervening hiatuses, condensed sedimentary sections, anoxic phases, and resedimentation cycles. Although primarily devised to serve as a regional biozonation, the scheme presented here has a unifying character because it can be applied to other Paleozoic basins in Brazil and Western Gondwanan regions where similar miospore successions are documented. A miospore assemblage zone recently described for the early Late Carboniferous interval of the Amazon Basin is also partly reviewed and integrated with the new biozonation for the older sections.

The composition and main biohorizons of Devonian miospore successions of Western Gondwanan regions are reviewed and compared to corresponding miospore zones of Southern Euramerica. The stratigraphic distribution of the most significant taxa is recorded in the main investigated basins of North Africa, Saudi Arabia and Brazil. With the exception of certain forms geographically restricted to Western Gondwana, most of the stratigraphically useful taxa are common to both Southern Euramerica and Western Gondwana. Successions of Western European-defined zones can be recognized and correlated in Western Gondwana regions on the basis of these common index species. Many Devonian miospore biozones defined in Western Europe are well represented in Western Gondwana, whereas some remain unrecorded or poorly characterized. The biozones may alternate with intervals with poor biostratigraphic resolution which can be attributed to various causative agents.

Varvelike rhythmites, usually laminated siltstones and shales with scattered clasts, are known from outcrops and well cores of the upper Cabeças Formation in the Parnaíba (Maranhão) Basin, Brazil, with sediments laid down under glacial and periglacial conditions. Palynological study from different lithologies, indicates a latest Famennian age (LN Zone). Sedimentological approach of one rhythmite indicates that the grain-size contrast clearly separate between silt and sand layers but that all layers, even the dark silty ones, show features characteristic of sediment-gravity flows. Lateral influx was permanent during the deposition of the sediment. Clay analyses reveal the predominance of kaolinite probably originated from Middle Devonian rocks. Latest Famennian miospores and acritarchs are present and confirm the marine character of the depositionnal environment but a large part (70%) of the palynological material is reworked from Givetian / Frasnian rocks. No reworked miospores from early to late Famennian can be demonstrated. At least two distinct source-areas of the reworked material, Givetian (or older) and Frasnian, can be recognized. Contemporaneous miospores are significally less present in the tillites and associated shale than in the laminites which suggest that they are produced locally, the glacial tongue, carrying the reworked part of the material, only partially overlapping adjacent environments. The rythmites are presumed to be true varves, the sandy layers being first settled after the local seasonal melting of the ice cover and the rush of fresh water supply into the sea, the silty layers being deposited when the spring water run-off decreases. The Vallatisporites mother-plant, believed to live in a swamp margin environment, might have been the first to produce spores immediately after the melting of the ice cover

This contribution presents the first detailed account of miospore assemblages from outcrop samples of Devonian and Lower Carboniferous rock units exposed along the Tocantins River valley, on the southwestern border of the Parnaiba Basin, Brazil. The miospore assemblages are discussed in the light of zonal schemes currently in use for Euramerican as well as western Gondwanan areas. Eight miospore assemblages are distinguished based on the recognition of selected index species. The six older assemblages are from the Pimenteira Formation and range in age from early Givetian to late early Frasnian. The seventh miospore assemblage concerns the Cabecas Formation and indicates a latest Famennian age. The eighth and youngest miospore assemblage is restricted to the Longa Formation and points out to an early middle Tournaisian age. The miospore results in this paper are compared to previous biostratigraphic works in correlative Devonian and Lower Carboniferous sections of the Parnaiba Basin. They contribute to a better understanding of complex field relationships of regional rock units, particularly as concerns the latest Famennian diamictites and the underlying glacio-eustatic unconformity.

Palynomorph distribution in Euramerica and western Gondwana, from the Latest Givetian to the Latest Famennian, may be explained, to some extent, by climatic changes. Detailed miospore stratigraphy dates accurately the successive steps of these changes. Interpretation is built on three postulates which are discussed: Euramerica at slightly lower latitudes than generally accepted by most paleomagnetic reconstructions; a conodont time-scale accepted as the most used available subdivision of time; and Late Devonian sea-level fluctuations mainly governed by glacio-eustasy. The Frasnian–Famennian timescale is also evaluated. The comparison, based on conodont correlations, between Givetian and most of the Frasnian miospore assemblages from, respectively, northern and southern Euramerica demonstrates a high taxonomic diversity in the equatorial belt and much difference between supposed equatorial and (sub) tropical vegetations. On the contrary, a similar vegetation pattern and therefore probably compatible climatic conditions were present from tropical to subpolar areas. A rather hot climate culminated during the Latest Frasnian when equatorial miospore assemblages reached their maximum width. The miospore diversity shows also a rather clear global Late Frasnian minimum which is also recorded during the Early and Middle Famennian but only in low latitude regions while, in high latitude, very cold climates without perennial snow may explain the scarcity of miospores and so, of vegetation. The Early and Middle Famennian conspicuous latitudinal gradient of the vegetation seems to attenuate towards the Late and Latest Famennian but this might be above all the result of the development, of cosmopolitan coastal lowland vegetations (downstream swamps) depending more on the moisture and equable local microclimates than on the probably adverse climates of distant hinterland areas. During that time, periods of cold climate without perennial snow cover and with rare vegetation may have alternated with less cold but wetter climates, thus giving rise to the development of mountain glaciers in high latitudes and explaining the jerking character of the global major marine regression. In high latitude regions, the development of an ice cap reaching sea level is only recorded by the end of the Latest Famennian, immediately below the DCB but, even if glacial evidences are not known at near the FFB, a short (0.1 Ma?) glaciation seems the best reasonable explanation of the major eustatic fall following the Kellwasser Event. The sudden growth and decay of a hypothetical Earliest Famennian ice sheet can be explained by the reduction and, later, increase in greenhouse capacity of the atmosphere. These changes in the atmospheric CO2 might have provoked changes in the mode of ocean-atmosphere operation. It may also be partly controlled by a volcanic paroxysm and/or bolide impacts. The Hony microtektites represent the best known evidence of the impact of extraterrestrial bodies on Earth corresponding to the UKW, and they are immediately followed by a regression, suggested by the quantitative analysis of acritarch assemblages. In the paleo-tropical Late Famennian, a peat-forming vascular plant community occurs for the first time and makes possible quantitative palynology of autochthonous sediments allowing the recognition of different swamp and near-swamp characteristic miospores. The early Latest Famennian starts with a widespread transgression which could correspond to the melting phases of the hypothetical Late Famennian mountain glaciers. During the end-Famennian, the coastal lowland vegetation has a worldwide distribution from sub-polar to equatorial regions. The climate has become less cold in high latitudes but wetter than before probably because the midlatitude cyclonic activity allows sufficient polar transportation of moisture to form large snow cover. Extensive coastal glaciers developed in different Bolivian and Brazilian basins, well dated by miospores. Rapid climatic changes characterize the onset of glaciation. The cyclic nature of climate allowed even intertropical marine faunas to reach occasionally the subpolar regions. For the plant kingdom, the crisis which follows the Hangenberg Event was more severe than the Late Frasnian Crisis.

The Poti Formation, which consists mainly of sandstones with minor proportions of carbonaceous shales and other siliciclastic lithologies, represents all the Visean strata thus far recorded in the Parnaiba Basin, northern Brazil. Well-preserved miospores featuring species with both Southern Euramerican and Gondwanan affinities have been recovered from this formation in four well sections. The most characteristic species are listed in this paper, and brief systematic descriptions are presented for the most significant species, along with comments on their biostratigraphy. A new generic combination is proposed: Cordylosporites magnidictyus (Playford and Helby) Loboziak and Melo comb. nov. Comparisons with miospores illustrated from the Grand Erg Occidental, Algerian Sahara, are tentatively proposed. In terms of the Western European Carboniferous palynozonation, miospore assemblages from the Poti Formation are assignable to the Perotrilites tessellatus – Schulzospora campyloptera (TC)– Raistrickia nigra – Triquitrites marginatus (NM) zonal range. This corresponds to the upper part of the Holkerian and the whole Asbian, which are British regional stages for the lower to middle parts of the upper Visean. The Visean age formerly attributed to biostratigraphic interval XII of Petrobras' regional palynostratigraphic scheme is therefore confirmed. As already noted in our recent investigations of the Faro Formation in the Amazon Basin and equivalent strata of the Solimoes Basin, latest Tournaisian and early to middle Visean sections are either absent or barren of characteristic miospores in the Parnaiba Basin as well.

A new species of trilete zonate miospores, Radiizonates arcuatus, is established for Lower Carboniferous Western Gondwanan forms hitherto ascribed misguidedly to Radiizonates genuinus (Jushko) Loboziak and Alpern (1978), a Russian Lower Carboniferous species. The latter binomen is, moreover, not a valid combination and is more correctly designated as Vallatisporites genuinus (Jushko) Byvsheva, 1980. R. arcuatus is, from records to date, confined to westerly parts of Gondwana (Brazil, North Africa and Middle East), in which it is characteristic of Early Carboniferous strata, albeit with some slightly older and slightly younger occurrences.

A miospore zonal scheme for late Early - Late Devonian strata of Western Gondwana is presented. Itis based on the first occurrences of both distinctive zonal taxa or groups of taxa of the most significative biozonations of Southern Euramerica and endemic Western Gondwanan species.

An emended diagnosis and generic reallocation are proposed for the trilete miospore Indotriradites dolianitii (Daemon, 1974) Loboziak et al., comb. nov. A new species, I. daemonii Loboziak et al., sp. nov., from Visean strata of Western Gondwana, is erected. These two species, together with I. zosteriformis (Playford et Satterthwait) Playford, 1991 from the Visean of Australia, belong to a cohesive morphological miospore category, here termed the Indotriradites dolianitii Morphon, which is evidently restricted to the Lower Carboniferous of Gondwana.

Grandispora riegelii Loboziak et Streel, 1989 is shown to be a junior synonym of Contagisporites permultus Daemon, 1974, which in its turn is to be correctly assigned to the genus Grandispora. An emended diagnosis is therefore proposed for Grandispora permulta, and previous data on its geographic and stratigraphic distribution are discussed. Grandispora permulta can be regarded as a useful indicator of Middle and early Late Devonian ages in Western Gondwanan regions. Reported occurrences of the species from Famennian or younger rocks are attributed to reworking from older Devonian strata.

A late Visean age within the late Holkerian–early Brigantian time span (TC–VF zonal range) is proposed for the highest, shalier, transgressive part of the Faro Formation in well 2-LF-1-AM and equivalent sections of other Amazon Basin boreholes, which in some cases have been misattributed to the underlying Oriximina Formation. Late Tournaisian–middle Visean microfloras (CM–TS zonal succession) are now regarded as absent in at least the Amazonian regions of northern Brazil. This supports the hypothesis of a regional unconformity separating the late Visean sequence from the latest Famennian/early late Tournaisian sequence in those areas. Palaeoenvironmental factors of uncertain nature seem to have controlled the presence or absence of miospore index-species (either of Euramerican or Gondwanan affinities) in the Amazon Basin. Such erratic nonoccurrences have led to miscorrelations of local miospore successions. Early to middle Visean sections are either missing or highly condensed in northern Brazil, and a similar situation may occur in North Africa and adjacent regions.

Miospore assemblages recovered from a shallow borehole (Caima PH-2) and outcrops near the Tapajos River (Itaituba area), on the southern margin of the Amazon Basin, permit the correlation of the Protosalvinia Zone in this region with the equivalent of the uppermost part of the VCo miospore Zone in the eastern USA. Therefore it is dated as late (not latest) Famennian (postera to early expansa conodont Zones). The Protosalvinia Zone also exists in the eastern USA but cannot be considered there as one single floral zone, its age varying, from place to place, from the middle to the late (not the latest) Famennian (one of the marginifera Zones to one of the expansa conodont Zones). As demonstrated in well 1RX1AM, miospore evidence points to an important intraformational gap separating the lower and upper parts of the Curiri Formation. The lower section (which contains the Protosalvinia Zone) lacks diamictites, and rests conformably on the upper, non-radioactive shales of the uppermost Barreirinha Formation, of similar late Famennian (VCo) age. The ‘upper Curiri unit’ contains diamictites, and invariably displays a latest Famennian (late ‘Strunian’, LE-LN) age; it may constitute the whole formation in areas where ‘lower Curiri’ strata are missing, due to either erosion or non-deposition.

The so-called “Namurian” taeniate bisaccates newly reported from the Amazon Basin of northern Brazil (Marques-Toigo et al. 1995) are demonstrated to be not older than Westphalian in the light of revised foraminiferal and palynological evidence. Nevertheless, marine microfossil data supports a slightly older age assignment (Westphalian A-B) than miospores (Westphalian C). Correlations of Carboniferous pollen assemblages in the Amazon Basin with those from the Parana Basin, in southeastern and southern Brazil, are hindered by the absence of diagnostic marine microfossils and coeval mid-Carboniferous strata in the latter.

An examination of Palaeozoic sections west of Cochabamba, and west of Lake Poopo, in western Bolivia, was conducted during a field expedition in 1991. The Rio Iglesiani valley, west of Cochabamba, surprisingly yielded a Middle Devonian age to all the visited sites, originally supposed to be Ordovician. This result is based on spores, shelly faunas (brachiopods and bivalves), and trilobites. The Copacabana de Andamarca section, west of Lake Poopo, is also dated as Middle Devonian on account of its rather rich fauna (bryozoans, corals, brachiopods, conulariids, hyolithids, tentaculitids, ostracodes, trilobites, crinoids, vertebrates). Both localities correlate to the Icla and/or Huamampampa Formation of the Tarabuco area and Subandean belt, and to the Belen and/or Sica Sica Formation of the northern Altiplano.

Late Lower and Middle Devonian miospores are identified in cuttings from well TRBH-1. A biostratigraphic zonation is proposed and compared with the miospore zonal scheme defined in Western Europe. All samples contained caved material. By graphic correlation with contemporaneous cored sequences previously analysed in Libya and Tunisia, the first appearance of Geminospora lemurata , a key species for defining the base of the Givetian, is evaluated.

The stratigraphical distribution of 11 miospore species found so far only in North Africa and Brazil are compared to the range of taxa which characterize the west European based zonation in order to establish accurate determinations. The zonate-camerate miospores that are more or less restricted to the Middle Devonian are the most frequent. Other taxa, often camerate with some tabulate ornamentation, first occur near the Givetian-Frasnian boundary. Three of them are restricted to Brazil. These species are more abundant in the early Givetian. During the late Givetian they are probably more numerous in North Africa than in Brazil. Their relative frequencies strongly decrease during the Frasnian. A greater climatic contrast between the two regions during the late Eifelian (?) and the late Givetian and Frasnian than during the early Givetian is inferred.

High-resolution miospore biostratigraphy depends upon accurate knowledge of taxonomy but also on the stratigraphical relationships between the miospore-based units and other biozones. Examples taken from the Devonian and Lower Carboniferous demonstrate that the Assemblage Zone concept and the lack of discrimination in evaluating the associated faunal and lithological data can lead to questionable conclusions. Suggestions are made for a more accurate definition of interval zones and related data.

Samples from the Menen Borehole (West Flanders, Belgium) provide new datation based on miospores for the Late Devonian and Early Carboniferous succession in the western part of the Namur Synclinorium. Despite the discontinuity and the heterogeneity (cores and cuttings of sampling), sediments of middle Famennian, uppermost Famennian (Strunian) and late middle to late Tournaisian are recognized. The implication of these data on the regional geology is emphasized.

Resume Les miospores de la partie devonienne du sondage tunisien MG-1 au Nord du Bassin d'Hammadah sont analysees et comparees aux donnees faunistiques disponibles. L'âge des differentes formations traversees par ce sondage est revu et conduit a la conclusion que l'Emsien et l'Eifelien sont representes par une sedimentation plus epaisse que les autres etages. Les faunes publiees provenant de ce sondage ne contredisent pas les resultats palynologiques et ceux-ci confirment l'opinion anterieure des auteurs que la stratigraphie du Devonien de la region est plus complexe qu'admis anterieurement.

Uppermost Devonian and Lower Carboniferous miospore Zones previously defined in western Europe areidentified in a borehole in the Amazonas Basin in Brazil. They range with some discontinuity from the uppermost Famennian to the lowermost Visean. Except for a few species which are listed, most of the taxa are common to Euramerica and Gondwana.

A review of miospores, faunas and megafloras of the Lower and Middle Devonian in Libya allows new conclusions to be drawn. The application of the Ardenne-Rhenish Devonian miospore zonation in Libya gives the following results. In the North Hammadah Basin, the base of the Tadrart Formation might well be strongly diachronous depsite the lithostratigraphical correlations shown on the base of “Gamma-Ray/Neutron” logs. At least the lower part of the Tadrart Formation in borehole MG-1 is within the lowermost part of the Lochkovian not at its base. In the southern margin of the Hammadah Basin, the Tadrart and Ouan-Kasa formations are probably not older than late Emsian, maybe early Eifelian. The Ouenine Formation I is often absent there or strongly reduced. The isochroneity of the (discordant) lower limit of the Tadrart Formation across the Hammadah Basin is far to be demonstrated. The Caledonian age of the discordance on the southern margin of the Hammadah Basin can obviously be challenged. In the eastern Murzuk area, the plant-bearing Tadrart-Emi Magri formations have a Middle Devonian age according to the plant fossils themselves. The discordance which separates these formations from the Acacus Sandstone at Dor el Goussa has to be late Early Devonian or Middle Devonian because the Acacus Sandstone “Psilophytes” cannot be older than Pragian and can even be younger (Emsian). There is obviously no available argument which could counteract the fossil floral data and prove that the discordance in the eastern Murzuk has the same age as the Silurian/Devonian transitional beds in the northern Hammadah Basin.

Resume Une etude conjointe des miospores et des Foraminiferes dans la coupe de l'Oued Zemrine (Maroc) a permis de dater du Tournaisien superieur et du Viseen moyen. Divers problemes de correlations biostratigraphiques avec les echelles belge et anglaise sont discutes.

New, hitherto unpublished miospore information from the Middle and Upper Devonian of the Parnaiba Basin, northeastern and northcentral Brazil, has enabled refinement of the chitinozoan zonation recently proposed for that basin. To a large extent, Devonian miospore zones defined for the Amazonas Basin can be also recognized in the Parnaiba Basin and other Western Gondwanan basins. The miospore zones are discussed and compared to the coeval Southern Euramerican miospore zonation, the regional Petrobras palynozones, and to the chitinozoan zonation of the Parnaiba Basin, additional Western Gondwanan regions, and other parts of the world.

A zonal subdivision of the Frasnian–Famennian transitional deposits in the Pripyat Depression and Timan–Pechora Province, based on a detailed palynological study, has been completed. The data obtained on miospores and conodonts from the Timan–Pechora Province enable a correlation to be made with the Standard Conodont Zonation. The lateral extent of the palynozones in Eastern Europe and the correlation with Western Europe are discussed. The following previously published new combinations are validated: Auroraspora speciosa (Naumova) Obukhovskaya, comb. nov., Corbulispora viminea (Nekriata) Obukhovskaya and Nekriata, comb. nov., Cristatisporites imperpetuus (Sennova) Obukhovskaya, comb. nov., Cymbosporites acanthaceus (Kedo) Obukhovskaya, comb. nov., Grandispora subsuta (Nazarenko) Obukhovskaya, comb. nov., and Verrucosisporites evlanensis (Naumova) Obukhovskaya, comb. nov.

In northwest and eastern Europe different miospore zonation schemes have been erected for the Famennian rocks, and correlation of these has proved problematical. However, in both regions of Europe Grandispora taxa are common elements in the respective Famennian spore successions, and it appears these taxa may have important intra-continental correlation potential. In order to assess this potential, a C.I.M.P. working group has undertaken a taxonomic study of the Grandispora complex in the Famennian of both regions. Representative material from Belarus, Poland, Germany, Belgium, France and Ireland has been exchanged, and then jointly studied, at four workshop meetings. A consensus of agreement has been reached on the morphological delineation and nomenclature of 13 species of Grandispora, and a description of each taxon is presented. One new species Grandispora tamarae is erected, and six new generic combinations are proposed. The stratigraphic range of each species in both regions is documented and calibrated with the respective conodont zonation schemes. It can be shown that many of the Grandispora species seem to have their first occurrence at similar stratigraphic levels. These new data allow detailed correlations of the Famennian miospore zonation schemes to be proposed.

Fifty-five miospores (including 7 new species and 3 new combinations) that range from Emsian to late Frasnian are identified, and 48 illustrated from 4 boreholes in the Ghadamis Basin. Their stratigraphic distribution is given and correlations made with established chronostratigraphic schemes. The Old Red Sandstone Continent miospore zonation can obviously be applied to this part of the Gondwanaland. The similarity of the miospore assemblages in both continents since at least the Emsian, suggests a close proximity of these continents during the middle and Upper Devonian.

Resume Des miospores et des Chitinozoaires bien conserves ont ete extraits de carottes de sondage provenant du bassin d'Illizi. L'analyse detaillee de la distribution verticale de ces microfossiles permet de dater avec precision les diverses formations du Silurien superieur et du Devonien, reconnues par sondage dans le Sud-Est du Sahara algerien. Cette etude biostratigraphique demontre d'autre part l'existence d'importantes lacunes liees a des emersions periodiques.

Resume De la comparaison entre des assemblages de miosporesd'âge Givetien-Frasnien de deux sondages realises en Libye et au Bresil dans des regions respectivement paleo-subtropicale et paleo-polaire, les auteurs concluent, pour cette epoque, a une certaine uniformite de la vegetation et par consequent du climat. Cette uniformite s'accentue du Givetien au Frasnien.

In the first place the author assesses the weight of the accumulation of palynological works, in the coal basins or groups of coal basins of Western Europe, as regards the Westphalian. A selection is then made of the most significant microspores. The distribution of these, qualitative and in some cases quantitative, allows the recognition of seven distinct zones in the Westphalian with boundaries corresponding to the most notable variations. The limits and subdivisions of the Westphalian are discussed, taking account of the information provided by these microfossils.

A new succession of about fifteen coal seams has been discovered, in overturned position, between the “faille du Midi” and the classical Kilits Series in the Caydamar mines, Heraclee Basin, Turkey (gallery −200/3400A). These beds, on the basis of plant spores, are Westpphalian A in age. The flora too is listed. Sixty-eight microspore and eighteen megaspore species were found. Comparison is made with spore assemblages from northern France.

Resume L'etude du sens de l'evolution de l'architecture de la fronde dans le genre Callipteridium Weiss , du Westphalien superieur et du Stephanien, a permis de determiner par extrapolation les caracteres que devaient presenter les frondes des ascendants directs appartenant au genre Margaritopteris Gothan , du Westphalien. Ce fil directeur a guide les recherches sur le terrain et a permis la decouverte d'echantillons verifiant le bien-fonde de l'hypothese de depart. Ce resultat positif et le sens de l'evolution constatee sur cette nouvelle portion de la lignee nous amenent a reproposer une hypothese quant aux caracteres de la fronde des representants encore plus anciens de cette lignee que l'on peut faire remonter pour l'instant avec une grande probabilite au Namurien inferieur et plus hypothetiquement au Dinantien. Ce travail a entraine par ailleurs une revision des especes correspondantes des bassins houillers du Nord de la France et de Sarre-Lorraine induisant un certain nombre de consequences au point de vue des correlations stratigraphiques.